Air-cooled engine



Feb. 16, 1937. J. G. DINTILHAC AIR-COOLED ENGINE Filed Feb. 6, 1935 2 Sheets-Sheet 2 -h1ven2or Jean Geor- ANor'ne Patented Feb. 16, 1937 UNITED STATES 2,070,565 AIR-COOLED ENGINE Jean Georges Dintilhac, Paris, France, assignor to Society Yacco S. A. F., Paris, France Application February 6,

1935, Serial No. 5,285

In Belgium December 18, 1934 4 Claims.

The present invention relates to air-cooled engines of the type in which the cylinders are positioned one behind the other, in a straight line. But it should be well understood that this ineludes all engines including at least one group of cylinders disposed behind one another parallelly to the engine shaft. In other words the invention applies not only to engineshaving a single group of cylinders disposed in a line parallel 10 to the engine shaft, but also to V-type engines,

x-type engines, H-type engines, or again-to engines including several groups of cylinders each group forming a line parallel to the engine shaft and all the groups being disposed in a radial 15 fashion about said shaft. The invention is more especially, although not exclusively, concerned with aircraft engines.

The object of the present invention is to provide an engine of this kind which is adapted to be cooled under better conditions than up to this time, and especially with a view to avoiding the formation of cold points on the cylinders, that is to say of portions of the walls of said cylinders that are cooled too intensely as compared with other portions of the cylinder walls.

In engines according to the present invention an aperture or passage is provided laterally of the longitudinal plane of the cylinders for the inlet of cooling air, and means are provided for 30 so guiding said air with respect to the cylinders that the outer walls of the latter receive this air substantially tangentially. In other words, with this arrangement, at least a portion of the cylinders .is not struck by cold air impinging 35 thereon at right angles thereto orsubstantially so.

According to another feature of the present invention, which concerns engines, of the type above referred to, provided with-a cowling admitting air into the interval separating the cylinders from a wall disposed laterally at a certain distance from said cylinders, this wall is arranged not at a uniform distance from all the cylinders, but obliquely with respect to the line 45 of cylinders in such manner that this distance decreases when moving toward the last cylinder to be cooled, in the direction of flow of the cooling air stream. This arrangement ensures a better distribution of the cooling airto the various 5o cylinders of the engine. A similar arrangement may be used for the wall disposed on thev other side of the line of cylinders, if this second wall exists. I

Still another feature of the present invention 55 consists in providing at least some of the cylinders with guiding means, such for instanceas deflecting metal sheets which serve to distribute the cooling air and eventually to prevent it from striking a portion of the outer wall of the cylinders at right angles thereto.

Other features of the present invention will result from the following detailed description of some embodiments thereof.

Preferred embodiments of the present invention will be hereinafter described, with reference to the accompanying drawings, given merely by way of example, and in which:

Fig. 1 is a longitudinal sectional viewof an airplane engine including a single line of cylinders, together with its cowling and its air cool-' ing system, some parts being shown in elevation, the whole being devised according to the present invention;

Fig.2 is a. corresponding plan view, partly in section;

Fig. 3 is a corresponding end view;

Figs..4, 5, and 6 are views, similar to Figs. 1, 2, and 3, respectively, corresponding to an engine of the V-type according to the present invention Fig. 7 is a partial diagrammatic cross sectional view of an arrangement according to the present invention in the case of anengine of the double radial type.

In the embodiment of Figs. 1 to 3, the engine, which is supposed to be of any conventional or other type including four cylinders disposed in a line, one behind the other, is disposed, in the known manner, inside a cowling C, surrounding most of said engine. This cowling includes two longitudinal walls, l and 2, disposed on either side of the longitudinal plane passing through the axes of all the cylinders.

One of these walls, for instance I, limits, be-

tween itself and the cylinders 3, a passage B into which air is allowed to penetrate, through at least oneopening 4 provided at the front part of the engine and laterally with respect to the longitudinal plane of the cylinders as mentioned above. The other wall, to wit 2, limits, on the other side of this plane, a passage B into which air flows from the first mentioned passage through the intervals between the cylinders and from which it flows out through at least one outlet orifice 5.

Further means are provided for eventually increasing the air pressure in the first mentioned. passage and compelling air to circulate between the cylinders, said,means consisting for instance of metal sheets I3 disposed on one side of cylinders ,3, in passage B so as'to stop a portion of the intervals between cylinders 3.

A device such as justabove described, without any other organ, does not comply with the conditions above stated, because air, flowing between the cylinders in the direction of arrows f, will strike some portions of said cylinders at right angles thereto, as at A, and these portions will generally be cooled too intensely ascompared with other portions of the cylinders.

In order to obviate this drawback, these portions A of the cylinders are protected against the direct cooling action of air. This protection should be particularly emcient for the bottoms of the cylinders (which are at the upper part in the case of an inverted engine, as shown by the drawings). This protection may, for instance be ensured by means of screens 6 disposed against these portions of the cylinders (or their cooling ribs) or at a small distance in front of these Portions A.

These screens 6, disposed for instance only in front of the upper ends of the cylinders, along a suitable height, may eventually be pf adjustable height, and even of adjustable width. h For the first cylinder of the engine, disposed immediately behind the opening I of the cowling, the screen may advantageously be replaced by a deflecting edge .1, which may be cut out of the sheet metal constituting the front wall 8 of cowling C. This deflecting edge may be provided either over the whole height or over a portion of the height of the cylinder.

Finally, at least one supplementary opening 9 may be provided for admitting air onto the head of the first cylinder, as well as into passage 3*. The means above described permit of improving the conditions under which engines of the type above stated are cooled by air. These cooling conditions may befurther improved or adjusted to the circumstances by making use of shutters or the equivalen disposed either on the inlet or the outlet orifices.

However it is advantageous to make use of. the following arrangement: The wall I of the cowling is so arranged that the section of passage B instead of being uniform over the whole of its length, as this was the case in devices of this kind up to this time, decreases toward the rear of the engine; For this purpose, wall I is suitably inclined with respect to the plane of the axes of the cylinders. Owing to this arrangement, a better distribution of the cooling air to the cylinders is obtained while, up to this time, the cowling arrangements of engines of this kind had the very serious drawback of letting most of the cooling air flow straight to the rear end, while the front cylinders were not sufiiciently cooled.

This arrangement all 2-, as shown in dotted lines at 2 in Fig. 2. This wall 2 would then be so inclined with respect to the longitudinal plane of the engine that the section of flow through passage B increases toward the outlet thereof.

Of course, in this case, as the longitudinal sections of metal sheets I and 2 are no longer parallel to the plane of the axes of the cylinders, the whole will be surrounded by an outer casing of suitable shape.

In order to improve the distribution of air to the cylinders of the engine still further, it is also possible, according to another feature of the present invention to provide each'cylinder (with the might also be applied to exception of the first one) on at least one part as I0, II, of V-shaped horizontal section for instance, so as to divide the air stream that'is to flow between two adjacent cylinders from the air stream that is to flow on toward .the next cylinders.

These metal sheets may be fixed on screens 6, or, since the latter can in this case be dispensed with because metal sheets 1'0 and Il may serve to protect portions A of the cylinders against the direct cooling action of the air, to portions A of the cylinders in place of screens 6.

All the arrangements that have been above described can of course be applied to engines in which the cylinders, although disposed behind one another, are arranged in a different manner.

For instance in the case of a V-type engine, each row of cylinders may be mounted between two walls I and 2 converging toward the engine shaft. The cooling air penetrates (Figs. 4 to 6) through two apertures 4 and 4 located in the interval between the two groups of cylinders.

These two apertures are separated from each two parallel rows, for example, in the case of X-type engines and of H-type engines.

In the case of radial cylinders, the front cylinders may be protected by the front wall 8 of the cowling, while the cylinders disposed behind will be protected by suitably disposed screens 6, eventually in combination with deflecting metal sheets such as 52, dividing the cooling air into separate streams (Fig. 7).

It is clear that in engines-as above described the cooling takes place under the best possible conditions and there is no risk that some portions of the cylinders will be cooled too intensely as compared with other parts of the cylinders.

While I have, in the above description, disclosed what I deem to be practical and efflcient embodiments of the present invention, it should be well understood that I do not wish to be limited thereto as there might be changes made in the arrangement, disposition and form of the parts without departing from the principle of the present invention as comprehended within the scope of the accompanying claims.

What I claim is:

1. In an air cooled engine having a'group of cylinders disposed in a straight line one behind the other, a device for the distribution of cooling air to the cylinders, which comprises, in combi+ nation, a cowling surrounding said cylinders provided with at least one inlet opening at the front part thereof positioned laterally with respect to the longitudinal plane passing through the axes of all these cylinders,and with at least one outlet opening at the rear end of said cowling, and

V-shaped screens disposed in front of at least a I portion of the sides of said cylinders, the apex of each of said screens projecting in a direction opposed to the flow of air for preventing the air In an air cooled engine having a group of cylinders disposed in a straight line one behind the other, a device for the distribution of cooling air to the cylinders, which comprises, in combination, a cowling surrounding said cylinders provided with at least one inlet opening at the front part thereof positioned laterally with respect to the longitudinal plane passing through the axes of all these cylinders and with at least one outlet opening at the rear end of said cowling, and 'two metal sheets in front of each of the cylinders, with the exception of the front one, so arranged that a section thereof by a plane at right angles to the axes of the cylinders has the shape of a v having its point turned toward said inlet opening, said metal sheets extending along at least a portion of the height of the cylinders, respectively.

3. A device according to claim 2 in which the edge of said inlet opening close to the front cylinder is bentin front of said last mentioned opening so as to protect said front cylinder from the direct action of air flowing through said opening. 7

4. In an aircooled engine having a group of cylinders disposed in a straight line one behind the other, a device for the distribution of cool- 7 ing air to the cylinders, which comprises, in combination, a cowling surrounding said cylinders, the front part of said cowling forming a screen for the first cylinder and having one inlet opening therein positioned laterally at one side of the longitudinal plane passing through the axes of all the cylinders and having a length corresponding to the length of' said cylinders, saidfront part having a second inlet opening therein and positioned at the other side of said longitudinal plane, said second opening being smaller than said first and adapted to admit the air only onto the head of the first cylinder, said cowling having at least one outlet opening at the rear end thereof, and screens disposed in front of the bottom parts of the sides of the rear cylinders facing in a direction opposed to the flowof air.

JEAN GEORGES DINTILHAC. 

